The approach an enforcement court should take to a prior decision of the Seat court on the validity of an arbitral award is harmonising in common law jurisdictions. In 2023, the Singapore Court of Appeal, in Republic of India v Deutsche Telecom AG,[1] found that transnational issue estoppel prevented India from resisting enforcement of an arbitral award by raising issues which already stood settled by the decision of the Seat court in Switzerland. Now, the Supreme Court of India in Nagaraj V. Mylandla v PI Opportunities Fund-I and others[2] has followed the approach taken in Singapore marking a high point for transnational issue estoppel.

Nagaraj is a seminal case. India now aligns with England & Wales[3] and Singapore[4] in supporting the notion that “a party who has succeeded before both the arbitral tribunal and the seat court [should]not be kept out of the fruits of its victory”.[5] Whilst the Supreme Court has made clear that ‘public policy’ at the enforcement court can defeat transnational issue estoppel, it has left open what ought to happen when an enforcement court decision is given prior to the Seat court and the approach when one considers decisions between enforcement courts. Jurisprudential thinking around the New York Convention and the ‘primacy’ of the Seat Court will continue, as will the application of transnational issue estoppel in civil law jurisdictions.

The Issues

Pursuant to a share acquisition and shareholding agreement (SASHA) between Mylandlas and the Respondent Investors, the Investors made investments in a company called FSSPL. The Investors were guaranteed an exit waterfall:

• A qualified IPO would be implemented on or before March 2016;

• If the qualified IPO failed, each Investor could participate in a secondary sale;

• If the secondary sale failed, FSSPL would buy-back shares from the Investors;

• If the buy-back also failed, the Investors could implement an IPO.

Failure by the Mylandlas (who were the promoters of FSSPL) to provide an exit to the Investors would constitute a material breach entitling the Investors to implement a strategic sale. When the Mylandlas failed to provide any exit mechanism, the Investors commenced arbitration with Singapore Seat and SIAC Rules. The Tribunal awarded damages (equal to the exit price) to the Investors. The Investors agreed that if they received the damages, they would surrender their shares in FSSPL (to avoid double recovery). If damages were not paid, the Investors were entitled to implement a strategic sale of their shares.

Seat Court – Singapore

The Mylandlas challenged the Award before the Singapore High Court on the basis that their right to a fair trial had been compromised because the Tribunal had failed to consider two defences: (i) the Buy-Back Defence – that the Investors’ surrender of shares amounted to a  buy-back by FSSPL of its own shares which was impermissible under Indian law; and (ii) the Waiver Defence – that the Investors had waived their right to a secondary sale. The Singapore High Court rejected the plea for annulment. It found that both defences had been considered and rejected by the Tribunal, that there was no breach of natural justice, and that allegations of errors of law or fact were not proper grounds to challenge an award.

The Enforcement Court – Madras High Court

The Investors filed enforcement proceedings before the Madras High Court in India. The Mylandlas objected to enforcement alleging that the Award contravened public policy. They raised the Buy-Back and Waiver Defences among others to justify their objection. The Madras High Court found that the Award was enforceable. It rejected the notion that the Award contravened Indian public policy and noted that the Mylandlas had raised the Buy-Back and Waiver Defences before the Singapore High Court which had decided the issues. The Madras High Court applied the doctrine of transnational issue estoppel and ruled that the Mylandlas could not raise defences that had been determined by the Seat court.

The Supreme Court of India

A decision granting enforcement to a foreign award cannot be appealed under the Indian Arbitration and Conciliation Act, 1996, but the Supreme Court has the power to grant special leave to appeal under Article 136 of the Constitution of India. In the context of enforcement of foreign awards, such leave is generally granted only to settle the law in light of a new or unique point. The Supreme Court gave special leave to the Mylandlas to appeal the Madras High Court’s decision to consider the doctrine of transnational issue estoppel. The Supreme Court conducted an elegant review of common law judgments and academic literature from which the following points emerge:

• Transnational issue estoppel applies if there is (i) a final and conclusive decision rendered in an earlier action, by (ii) a foreign court of competent jurisdiction, between (iii) the same parties or their privies, on (iv) the same issue. If these conditions are satisfied, there can be no re-litigation on the same issue by the same parties in subsequent proceedings;
• Preclusive effect will only arise if there has been a full contestation and decision on the issue and the decision is recognisable in the subsequent forum. The contours of transnational issue estoppel mean that if a party raised the same or similar issues in a previous proceeding, or could have but failed to do so, such party would be precluded from raising the same issue in subsequent proceedings;
• The doctrine does not have universal applicability. It will not apply if the ‘issue’ is forum-specific as opposed to forum-neutral;
• Applicability of the doctrine also depends upon whether the previous decision was rendered by an enforcement court or a Seat court. Seat courts tend to perform a more comprehensive review and their decisions deserve primacy, the Primacy Principle.[6]

The Supreme Court held that transnational issue estoppel will not apply if the ‘issue’ in question concerns Indian public policy. This is because public policy necessarily differs from State to State. Irrespective of previous decisions, second-seized courts will be better placed to review matters where their own public policy is concerned. However, Readers should note that the doctrine cannot be avoided by re-calibrating settled issues into a different form so as to take advantage of a new forum. If matters have been closed by a competent court, a party cannot raise the same matters again [at 83]:

“In this regard, we may also note that by giving a different colour to a factual issue, it is not open to a party to the foreign award to seek to bring it within the ambit of Section 48(2)(b) of the Arbitration Act by raising a ‘public policy’ ground. The doctrine of ‘transnational issue estoppel’ would bar the same.” [emphasis added]

Put simply, the Supreme Court held that the Mylandlas were barred from raising the Buy-Back and Waiver Defences. It found that their defences did not relate to public policy, and that the Mylandlas were simply giving the defences a different colour to obtain a merits-based evaluation.

What Next for Transnational Issue Estoppel

The common law use of transnational issue estoppel is ‘pro- arbitration’ and so aids efficiency in international arbitration by bringing finality. Where a Seat court has decided matters, the prevailing view is that enforcement courts ought to follow the Seat court.  The position is not so settled when one considers an enforcement court deciding prior to the Seat court.  The ‘Primacy Principle’ and its relationship with the New York Convention need further judicial analysis as do the precise contours of transnational issue estoppel when dealing with civil code courts and a mixture of common law and civil law courts.

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^[1] [2023] SGCA (I) 10.

^[2] 2026 INSC 298.

^[3] Hulley Enterprises Ltd and others v. The Russian Federation [2025] EWCA Civ 108.

^[4] Republic of India v Deutsche Telekom AG [2023] SGCA(I) 10.

^[5] Sundaresh Menon, ‘Arbitration and the Transnational System of Commercial Justice: Charting the Path Forward’, Asian International Arbitration Journal Volume 20 Issue 2 (2024), pp. 71.

^[6] Republic of India v Deutsche Telekom AG [2023] SGCA (1) 10; Sacofa Sdn Bhd v Super Sea Cable Networks Pte Ltd and another [2024] SGHC 54.